Expansion tank with improved single diaphragm

Abstract

An improved expansion tank is provided for at least temporarily storing a pumped liquid under pressure, the expansion tank comprising a thin walled outer shell formed of two substantially hemispherical domes joined together, either directly or at the two ends of a central, substantially cylindrical section, and a flexible diaphragm located internally of the tank and secured to the inner surface of the shell of the tank to divide the internal volume of the tank into a fluid-tight section holding a gas under pressure and a fluid-tight section for holding an aqueous liquid under pressure. The improvement comprising diaphragm coupling ring formed as a discrete part of the diaphragm tank that can be fabricated independent of the domes and any cylinder. The diaphragm coupling ring provides a robust, leak-proof seal with the diaphragm, so that it can be connected onto an inner surface of an expansion tank in a separate, secondary operation.

Description

BACKGROUND OF THE INVENTION[0001]Expansion tanks are known for use in flow systems for controlling flow of liquid under varying pressures. Most commonly, expansion tanks comprise a substantially cylindrical housing terminated on each end by a substantially hemispherical dome section. The entire combined tank being most preferably suitable for isotensoidal reinforcement by wrapping with equally stressed filaments. In some cases, the cylindrical housing may be shortened or absent, such that the entire shape is spherical, comprised of the two domes. The housing and domes further contain a bladder-type diaphragm that divides areas of a liquid and a pressurized gas. For a general discussion of expansion tanks and bladder-type diaphragms, see U.S. Pat. No. 4,784,181 to Hilverdink entitled “Expansion Tank with a Bladder-Type Diaphragm”.[0002]In expansion tanks, it is critical to maintain a liquid and gas-tight barrier between the liquid and pressurized gas, as well as the outside environme...

AI Technical Summary

Benefits of technology

The invention is about improving the sealing of expansion tanks used in industrial applications. The first improvement is a separate diaphragm coupling ring that can be easily joined to the tank using compatible equipment and processes. The second improvement is the use of tie-layers to join the diaphragm and tank sections together, creating a stronger and more reliable seal that is resistant to adhesive failures under the operating conditions of expansion tanks. Overall, these improvements enhance the performance and flexibility of expansion tanks.

Problems solved by technology

Known processes to attach diaphragms to tanks only produce adhesion between the diaphragm and the surface layers of the tank wall; these joints are highly susceptible to adhesive failures under the operating conditions of expansion tanks.

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